Manual hydraulic control circuits and cable control systems for buckets, rippers, blades, and other work implements are commonly employed within construction equipment used today. For example, an operator has to adjust the height, angle, and the tilt of the bulldozer blade at the beginning of every dozing operation. With each repositioning of the implement, the overall efficiency of the operation is decreased.
Automatic blade control systems using lasers have been proposed. However, such a system is not practical in earthmoving equipment because of the severe operating conditions.
One prior art example of a hydraulic motor control system is shown in U.S. Pat. No. 4,194,365 to Stoufflet et al issued Mar. 25, 1980. In this system, a single valve is selectively operated in either an automatic mode or a manual mode. A controller automatically regulates the return of the turret of a hydraulic excavator to a desired stopping position by taking into consideration the kinetic energy of the rotating turret.
A known automatic blade positioning device is shown in Japanese Patent Publication No. (Sho 62-24579) to Kabushiki Kaisha Komatsu Seisakusho issued May 29, 1987. In this arrangement, the blade is automatically controlled by detecting the difference of the rotational angle of two lift cylinders. This system uses the vehicle frame as its reference and the blade position can be repositioned only with respect to the frame.
The number of tasks in earthmoving operations have greatly increased and often distract from overall efficiency. The operator's view is often obstructed by the implement and is subject to parallax. Thus considerable time can be spent in repositioning an implement.
The present invention is directed to overcome one or more of the problems set forth above.